#include <bits/stdc++.h>
using namespace std;
bool div3(int x)
{
    if(x%3 == 0)
        return true;
    else
        return false;
}
int main() {
    vector<int> number(1000);
    //求三角形的面积
    auto area = [](int a,int b,int c){return abs((a-(a+b+c)/2)*(b-(a+b+c)/2)*(c-(a+b+c)/2));};
    int a = 3,b = 4,c = 5;
    cout<<area(a,b,c)<<endl;
    generate(number.begin(),number.end(),rand);//生成器用来在迭代器之前生成rand的返回值
    int count = count_if(number.begin(),number.end(),[] (int n){return n%3 == 0;});
    cout<<count<<"\n";
    return 0;
}